I. Field of the Invention
The invention relates to a process for the preparation of certain cyano-substituted cyclopropanecarboxylic acid esters by reacting an aldehyde, a salt of hydrocyanic acid and a 2-halocyclobutanone.
II. Description of the Prior Art
According to U.S. Pat. No. 3,835,176, addition of substituted cyclopropanecarbonyl halides and m-substituted benzaldehydes, if necessary dissolved in an aprotic solvent, to an aqueous solution of sodium cyanide or potassium cyanide and stirring of the mixture obtained until no more conversion takes place, affords the desired esters. The cyclopropanecarboxylic acids can be prepared and converted in a known manner to the corresponding cyclopropanecarbonyl halides.
Such a process has the disadvantages that the cyclopropanecarboxylic acids and their carbonyl halides must be prepared in separate stages.
The present invention obviates this disadvantage.